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Locomotion is a complex behaviour that requires the coordination of multiple body segments and muscle groups. Here we investigated how the weakness and spasticity in individuals with Hereditary Spastic Paraplegia (HSP) affect the coordination patterns of the lower limbs. We analysed kinematics and electromyographic (EMG) activity from 12 leg muscles in 21 persons with HSP and 20 control subjects at matched walking speeds. To assess the locomotor coordination, we examined the covariation between thigh, shank and foot elevation angles by means of principal component analysis and the modular organization of EMG patterns using the non-negative matrix factorization algorithm. The characteristic features of the HSP gait consisted in changes of the elevation angles covariation, the shape of the gait loop, reduced range of motion of the distal segments and significantly lower foot lift. The EMG factorization analysis revealed a comparable structure of the motor output between HSP and control groups, but significantly wider basic temporal patterns associated with muscles innervated from the sacral spinal segments in HSP. Overall, the applied methodology highlighted the impact of the corticospinal degeneration and spasticity on the coordination of distal limb segments and basic muscle modules associated with distal spinal segments. [ABSTRACT FROM AUTHOR]

Abstract: Homozygosis for wolframin (WFS1) mutations determines Wolfram syndrome (WS), and common polymorphisms of WFS1 are associated with psychiatric illnesses and dependence behaviour. To test the influence of WFS1 polymorphisms on medication overuse headache (MOH), a chronic headache condition related to symptomatic drugs overuse, we analyzed 82 MOH patients for the WFS1 His611Arg polymorphism, and performed a comparison between clinical features of Arg/Arg (R/R) and non-R/R individuals. Individuals harbouring the R/R genotype showed significantly higher monthly drug consumption (t =−3.504; p =0.00075) and more severe depressive symptoms on the BDI questionnaire (t =−3.048; p =0.003) than non-R/R. WFS1 polymorphism emerged as the only significant predictor of drug consumption, at the multivariate regression analysis (F =12.277; d.f.=1,80; p =0.00075, adjusted R 2 =0.122). These results implicate WFS1 in the clinical picture of MOH, may be through an influence on need for drugs as in other conditions of abuse behaviour. [Copyright &y& Elsevier]

To investigate whether prefrontal cortex (PFC) activation is linked to compensatory mechanisms (time–distance parameters) or to gait features (kinematic parameters) specifically related to the functional role of the cerebellum in ataxic patients. We performed a correlation analysis between the PFC metabolic profile during gait and time–distance and kinematic parameters in a sample of 19 patients affected by neurodegenerative gait ataxia and 15 age/sex matched healthy subjects. PFC metabolism was evaluated by a 2-channel functional near-infrared imaging system while gait analysis was performed using a stereophotogrammetric system. We found a positive correlation between the PFC metabolism and the step width (the correlation coefficient was r : 0.54, p = 0.02 for the right PFC, and r : 0.50, p = 0.03 for the left PFC). No correlation was found between PFC activity, the other time–distance parameters and the intra-subject variability of gait. PFC activation during ataxic gait correlates with step width and therefore it seems involved in maintaining compensatory strategies rather than due to primary cerebellar deficits. To our knowledge this is the first study correlating cortical activity and gait characteristics in order to assess how cerebral cortex is modulated during a pathological gait. [ABSTRACT FROM AUTHOR]